Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

a question about PWM in DC-DC converter.

Status
Not open for further replies.
B

batistuta

Member level 5
Joined
Jun 14, 2007
Messages
94
Helped
4
Reputation
8
Reaction score
0
Trophy points
1,288
Activity points
1,845
i have a question about dc-dc converter during study it, as we all known, one of PWM input signal always a saw-tooth wave(triangular wave) the other is a error-signal from error amplifier,so the out is a PWM signal.
my question is why not use a dc level signal to replace the saw-tooth wave? so it is a common comparator,it also can ouput a rectangular waveform,if so, the dc-dc circuit is more simple.(means we do not need the circuit to generate saw-tooth wave)
can anyone tell me why we not do this?
thanks.
 

I assume you are reading some books, and recommend you to look at the waveforms. If you compare DC (your idea) to DC (error amp output), you only get DC. Well, you can make the system to oscillate, but PWM circuit usually uses constant frequency. The idea is to change the duty cycle at a constant frequency.
S. H.
 

shwoo said:
I assume you are reading some books, and recommend you to look at the waveforms. If you compare DC (your idea) to DC (error amp output), you only get DC. Well, you can make the system to oscillate, but PWM circuit usually uses constant frequency. The idea is to change the duty cycle at a constant frequency.
S. H.
Click to expand...

hi,S.H thanks for your reply.
is error amplifier ouput a DC level???
 

EA's output is relatively stable, with a little ripple due to converter's output.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top